Cooper in awe of De Niro's acting ability

Bradley Cooper found it "very easy" to work alongside Robert De Niro.

The 37-year-old star was in awe of the Hollywood legend on the set of David O. Russell's forthcoming romantic comedy movie 'Silver Linings Playbook' - which sees the 'Meet the Parents' actor play the 'Hangover' star's father Pat Sr. - because he made "difficult scenes" appear "effortless".